Merge changes Id806633d,I05e945f3,Ieac84040,I18eb8cc0,If11c298e

* changes:
  Fix missing source module with ALLOW_MISSING_DEPENDENCIES=true
  Convert Visit*Deps from blueprint.Module to android.Module
  Move first/last unique elements utility functions to android package
  Move ModuleContext.ModuleBuild to ModuleContext.Build
  Make android.ModuleContext not include blueprint.ModuleContext